Synthesis of new unsymmetrical polyarylester dendrimers

Preparation of polyarylester dendrimers containing 2-(hydroxymethyl)-1,4-butanediol and 2,2-bis(hydroxymethyl)-1,4-butanediol cores is described. These polyarylester dendrimers are unsymmetrical with respect to chain lengths and function as model systems for studying in vitro controlled drug release systems. Reaction conditions for deprotection of trichloroethyl group of the dendritic wedges have been improved.     

Long range phosphorus-phosphorus coupling constants in bis(phosphorylhydroxymethyl)benzene derivatives

Long range spin-spin couplings found between two phosphorus atoms are quite rare phenomena. A new example of such a coupling through seven bonds is described for 1-[(diethoxyphosphoryl)butyryloxymethyl]-4-[(diethoxyphosphoryl)hydroxymethyl]benzene and 1,4-bis[phosphorylhydroxymethyl]benzene and through six bonds for tetraethyl phenylene-1,3-(bishydroxymethylphosphonate). Coupling constants in this system are also well predicted by theoretical studies.     

2,4-Bis(hydroxymethyl)aniline as a building block for oligomers with self-eliminating and multiple release properties

Linear self-eliminating (LSE) systems are oligomers of branched self-eliminating linkers that disassemble upon a single triggering event under complete degradation of the linear backbone, accompanied by the release of side-chain bound effector molecules. Enabling a controlled and almost simultaneous release of different effectors (drugs) in defined ratios, LSE systems may gain importance for the development of novel combination therapeutics. On the basis of the well-known self-eliminating p-aminobenzyloxycarbonyl (PABC) linker, 2,4-bis(hydroxymethyl)aniline was considered a suitable branched linker for building LSE systems that degrade by 1,6- and 1,4-benzyl elimination reactions. A first LSE model system based on this linker was prepared in a simple procedure and was shown to release its effector payload efficiently after activation. In addition, elimination model compounds were synthesized to study the release behavior of LSE systems based on 2,4-bis(hydroxymethyl)aniline. It was found that chain degrading 1,6-benzyl elimination occurs much faster than the effector releasing 1,4-elimination.     

季戊四醇双缩醛的合成

以苯为溶剂，ＴｓＯＨ为催化剂合成了几种长直链的季戊四醇双缩醛。     

Synthesis and characterization of some copolycarbonates of 2,2-bis (4-hydroxyphenyl)propane (bisphenol-A) and 1,4-bis(hydroxymethyl) cyclohexane

Copolycarbonates of Bisphenol-A (BPA) and 1,4-bis(hydroxymethyl)cyclohexane have been prepared. The resulting copolymers have slightly lower glass-transition temperatures than BPA polycarbonate homopolymers. Crystallisation and annealing effects are also reduced. The results are generally similar to those obtained with copolymers of BPA and 1,4-bis(hydroxymethyl)decafluorobicyclo(2,2,1)-heptane [1] but the differences are less marked.     

Cubane derivatives

An efficient procedure for the preparation of 1,4-bis(hydroxymethyl)cubane by reduction of cubane-1,4-dicarboxylic acid or its dimethyl ester with aluminum hydride was developed. The molecular structure of 1,4-bis(hydroxymethyl)cubane was established by X-ray diffraction analysis. For Part 3, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1387–1390, July, 1998.     

2,3-二羟甲基-2,3-二硝基-1,4-丁二醇四硝酸酯的合成、晶体结构及性能研究

以硝基甲烷为起始原料,经缩合、环化、氧化耦合、脱缩酮及硝化等5步反应合成了2,3-二羟甲基-2,3-二硝基-1,4-丁二醇四硝酸酯(BHDBT),总收率为36.1％,并采用核磁共振谱、红外光谱以及元素分析等进行了结构表征.用浓盐酸代替氯化氢气体,改进了关键中间体2,3-二羟甲基-2,3-二硝基-1,4-丁二醇(BHDB)的合成方法,并确定最佳反应条件为:刀(浓盐酸):n(BDND)=1.1∶1,反应温度55℃,时间4h,收率为94.8％.首次发现了BHDB和BHDBT的亚甲基质子具有磁不等价性,并从理论上分析其产生的原因.培养了BHDBT单晶,四元衍射晶体结构解析表明:BHDBT属于单斜晶系,空间群P2(1)/n,晶胞参数:a=0.81944(11) nm,b=2.3365(3) nm,c=0.85838(11) nm,a=90°,β=113.501(2)°,y=90°,V=1.5072(3) nm3,Z=4,Dc=1.852 g·cm-3,μ=0.189 mm-1,F(000)=856.BHDBT熔点为86.37℃,分解峰温度为185.79℃(DSC),摩擦感度为100％ (3.92 MPa,90°),特性落高H50为10.0 cm(5 kg).     

Crosslinking of sulphonated poly (ether ether ketone) using aromatic bis(hydroxymethyl) compound

2,6-Bis(hydroxymethyl)-4-methyl phenol and 1,4-bis(hydroxymethyl) benzene have been used as crosslinkers in sulphonated poly (ether ether ketone) (SPEEK DS 65%, IEC 1.84 mequiv./g) for the preparation of proton exchange membranes (PEMs). Crosslinking of SPEEK has been achieved by thermally activated bridging of the polymer chain with the hydroxymethyl group of crosslinker through condensation reaction with sulphonic acid group. The physico-chemical properties of uncrosslinked and crosslinked membrane were evaluated in terms of ion exchange capacity (IEC), water uptake, ionic conductivity and mechanical properties. The crosslinked membrane showed controlled swelling, ionic conductivity of 25–50 mS/cm at 80 °C and good mechanical properties. The chemical stability of the crosslinked membranes was studied by Fenton's test. The % loss in weight and changes in physico-chemical properties of the treated membranes were determined.     

Reactions of 1,4-bis(tetrazole)benzenes: formation of long chain alkyl halides

The reactions of 1,4-bis[2-(tributylstannyl)tetrazol-5-yl]benzene with α,ω-dibromoalkanes were carried out in order to synthesise pendant alkyl halide derivatives of the parent bis-tetrazole. This led to the formation of several alkyl halide derivatives, substituted variously at N1 or N2 on the tetrazole ring. The crystal structures of 1,4-bis[(2-(4-bromobutyl)tetrazol-5-yl)]benzene (2-N,2-N′), 1,4-bis[(2-(4-bromobutyl)tetrazol-5-yl)]benzene (1-N,2-N′) and 1,4-bis[(2-(8-bromooctyl)tetrazol-5-yl)]benzene (2-N,2-N′) are reported. Further discussion involves the structure of 1,4-bis[2-(6-bromohexyl)-2H-tetrazol-5-yl]benzene (2-N,2-N′) previously reported.     

Synthesis of ethers and esters of 1,4-di-N-oxide of 2,3-bis(hydroxymethyl)quinoxalm under conditions of interfacial catalysis

Esters and ethers of the 1,4-di-N-oxide of 2,3-bis(hydroxymethyl)quinoyaline have been obtained under conditions of interfacial catalysis in a chloroform-water system. The catalytic activities of tetrabutylammonium bromide and cetyltriethylammonium bromide have been compared in the synthesis of the acetate, benzoate, and 4-nitrobenzoate of the 1,4-di-N-oxide of 2,3-bis(hydroxymethyl)quinoxaline.St. Petersburg State Technological Institute, St. Petersburg 198013. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 816–820, June, 1994. Original article submitted June 29, 1994.     

Fluorescence quenching and laser photolysis of dipyrrolylbenzenes in the presence of chloromethanes

Fluorescence quenching of 1,4-bis(1H-pyrrol-1-yl)benzene, 1-(1H-pyrrol-2-yl)-1-(1-vinyl-1H-pyrrol-1-yl)benzene, and 1,4-bis(1-vinyl-1H-pyrrol-2-yl)benzene with chloromethanes (methylene chloride, chloroform, and carbon tetrachloride) in solvents with different polarities follows electron-transfer mechanism. The occurrence of an electron-transfer step is confirmed by formation of short-lived pyrrolylbenzene radical cations. An exception is quenching of fluorescence of 1,4-bis(1-vinyl-1H-pyrrol-2-yl)benzene in n-hexane in the presence of CCl₄ and CHCl₃ and in pure CCl₄. In this case, neutral 1,4-bis(1-vinyl-1H-pyrrol-2-yl)benzene^·-Cl radical is formed via recombination of 1,4-bis(1-vinyl-1H-pyrrol-2-yl)benzene radical cation and chloride anion. A relation was found between the nature of the short-lived species detected by laser photolysis and stable product obtained by stationary photolysis.     

Electronic coupling in tetraanisylarylenediamine mixed-valence systems: the interplay between bridge energy and geometric factors

We have investigated three organic mixed-valence systems that possess nearly identical inter-redox site distances and differ by the nature of the bridging units benzene, naphthalene, and anthracene: the N,N,N',N'-tetra(4-methoxyphenyl)-1,4-phenylenene-diamine radical cation (1+), the 1,4-bis(N,N-di(4-methoxyphenyl)-amino)naphthalene radical cation (2+), and the 9,10-bis(N,N-di(4-methoxyphenyl)amino)anthracene radical cation (3+). The electronic interactions in these systems have been studied by means of gas-phase ultraviolet photoelectron spectroscopy, vis/NIR spectroscopy, and electronic-structure calculations. The experimental and theoretical results concur to indicate that the strength of electronic interaction decreases in the following order of bridging units: benzene > naphthalene > anthracene. This finding contradicts the usual expectation that anthracene is superior to benzene as a driving force for electronic communication. We explain these results in terms of a super-exchange mechanism and its strong dependence on steric interactions.     

Phenylene-containing organosilicon compounds

Summary By condensation of sodium triphenylsilanolate with 1,4-bis(dimethylchlorosilyl)benzene, we synthesized for the first time 1,4-bis[dimethyl(triphenylsiloxy)silyl]benzene, which is a crystalline substance with m.p, 237–238°, distilling at 465–475° without decomposition.     

The development of corannulene-based blue emitters

Novel blue emitters were synthesized based on the fullerene fragment corannulene. 1,2- bis(corannulenylethynyl)benzene and 1,4-bis(corannulenylethynyl)benzene were designed, synthesized, and shown to exhibit significant red shifts in their absorption spectra as compared to that of the parent corannulene. Photoluminescence studies show both 1,2- bis(corannulenylethynyl)benzene and 1,4- bis(corannulenylethynyl)benzene gives enhanced blue luminescence compared to the parent corannulene structure. 1,4-bis(corannulenylethynyl)benzene was observed to give intense blue luminescence when excited at 400 nm. DFT and TD-DFT calculations were performed and shown to be consistent with the observed experimental results.     

二代螺环树形化合物1,2,3,4,5,6,7,8,9,10,11,12-十二氢-2,2;6,6;10,10-三[3,3-二(烷氧羰基)-1,1-环亚丁基二甲氧基]三亚苯基的合成

以1,4-环己二酮、丙二酸二乙酯及多元醇等为原料, 经过两次“一锅煮”法合成了六种二代螺环树形化合物1,2,3,4,5,6,7,8,9,10,11,12-十二氢-2,2;6,6;10,10-三[3,3-二(烷氧羰基)-1,1-环亚丁基二甲氧基]三亚苯基螺环树形化合物, 其中烷氧基为异戊氧基、三羟甲基甲氧基、2,2-二溴甲基-3-羟丙氧基、2,2-二羟甲基丙氧基、二羟甲基膦甲氧基和(N-羟甲基-N-二羟甲基氨基乙基)甲氧基. 利用IR, NMR, MS和元素分析对合成的化合物进行了结构认证, 对影响反应的因素进行了讨论.     

Synthesis,structural characterization,and Hirshfeld surface analysis of three cocrystals based on flexible bis(benzimidazole) derivatives with aromatic carboxylic acids

Research on Chemical Intermediates - Based on 1,3-bis(2-methylbenzimidazole)propane (L1), 1,4-bis(2-methylbenzimidazole)butane (L2) and 1,4-bis(2-methylbenzimidazol-1-ylmethyl)benzene (L3) with...     

Hydroxycruciforms: amine-responsive fluorophores

The synthesis of three hydroxy-substituted cruciforms (XF, 1,4-bis(4'-hydroxystyryl)-2,5-bis(4'-methoxyphenylethynyl)benzene, 1,4-bis(4'-methoxystyryl)-2,5-bis(4'-hydroxyphenylethynyl)benzene, and 1,4-bis(4'-hydroxystyryl)-2,5-bis(4'-hydroxyphenylethynyl)benzene) starts with a Horner reaction followed by a Sonogashira coupling and subsequent deprotection. The three herein described XFs contain either two or four free phenolic hydroxyl groups. All three XFs were subjected to photometric UV/Vis titrations in a methanol/water mixture. The respective pK(a) values were obtained by data deconvolution. As the three XFs display a significant change in emission color upon photoinduced deprotonation, the XFs were taken up in different solvents and exposed to twelve amines. The amine-dependent change in emissivity of the tetrahydroxy XF is sufficiently distinct in the eight solvents that all of the inspected amines are discerned by a linear discriminant analysis. The tetrahydroxy XF in different solvents forms a sensor array, the response of which is based on the excited-state proton transfer (ESPT) to amines and mediated by the choice of the battery of solvents that are utilized.     

Effect of chromophore-charge distance on the energy transfer properties of water-soluble conjugated oligomers

The synthesis of 1,4-bis(9,9'-bis(3"-(N,N,N-trimethylammonium)-propyl)-2'-fluorenyl)benzene tetrabromide (C3), 1,4-bis(9,9'-bis(4"-(N,N,N-trimethylammonium)-butyl)-2'-fluorenyl)benzene tetrabromide (C4), 1,4-bis(9,9'-bis(6"-(N,N,N-trimethylammonium)-hexyl)-2'-fluorenyl)benzene tetrabromide (C6), and 1,4-bis(9,9'-bis(8"-(N,N,N-trimethylammonium)-octyl)-2'-fluorenyl)benzene tetrabromide (C8) is reported. Fluorescence energy transfer experiments between C3-C8 and the acceptors pentasodium 1,4-bis(4'(2",4"-bis(butoxysulfonate)-styryl)styryl)-2-(butoxysulfonate)-5-methoxybenzene (3), fluorescein labeled single-stranded DNA and fluorescein labeled double-stranded DNA in water, buffer, and methanol reveal the importance of hydrophobic and electrostatic forces in determining chromophore-chromophore close proximity. In water, the oligomers with longer side chain length show better energy transfer, as well as higher Stern-Volmer quenching constants (K(sv)), largely due to a stronger hydrophobic attraction between the optically active components. In methanol, the differences in energy transfer are leveled, and the oligomers with shorter side chain lengths show higher K(sv) values. Compounds C3, C4, C6, and C8 were also used to dissect the different contributors to DNA hybridization assays based on cationic conjugated polymers.     

单分散PPE齐聚物的合成及其荧光性质

合成了PPE的齐聚物{1,4-二[3,5-二（3-甲基-3-羟基-1-丁炔基）苯炔基]苯）（4）,通过^1H—NMR对其结构进行表征,并对其荧光性质做了研究。研究结果表明引入四个2-甲基-2-羟基-丁炔基作为取代基团后,溶解性提高。取代基的引入导致齐聚物4旋转阻力增大,溶液荧光有明显的精细结构。而4具有较好的荧光单色性,因而是一种潜在的新型荧光发射材料。     

Microwave-assisted synthesis of 1,4-bis(difluoromethyl)benzene

A fast, mild, and practical microwave-assisted protocol for synthesis of 1,4-bis(difluoromethyl)benzene from 1,4-bis(dichloromethyl)benzene and KF was developed. The new protocol increased the yield and reduced the reaction time significantly in contrast to the conventional heating procedure. Also, the synergistic effect of a composite phase transfer catalyst was studied.